Spitfire & GT6 Forum

I have a 79 Spitfire and the brake pedal has started to slowly go to the floor when the brakes are applied. Thought it was air in the system so I have bleed them several times. The pedal first works as required and the car stops great. But if you leave pressure on the pedal it goes down. The cylinder is a duel piston type. I got the rebuild kit, but when I took it apart I can not get the second piston out in order to change the seals. What is the trick to get it out. Would hate to have to get a new cylinder if I can just fix this one.
So any ideas?

Pete

I often hear that is a trick. I think a lot of guys will use air input from the outlet pipe. There used to be a special tool to grab it with but I have not seen one of those for years. Hopefully someone will have a good answer for you soon.
Dan

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Dan Aycock
Walla Walla, Wa.
Yellowhawk Valley Spitfires
69, 69, 72, 75, 78, 79 Spitfires
TRF# 006047

Had the same difficulty !! Take out the rear rubber. Push a bit on the rear piston. This relives the pressure on the little pin in the area below the rear rubber.

If the rear piston is still stuck, I used a 1 1/4 pipe cap over the end of the casting and rapped it smartly on a vice to bring it forward enough to use pliers.

Alan

Get an air nozzle with a rubber tip, remove the bleeder screw and apply air pressure. Make sure you have a rag at the end to catch the piston. This has worked for me every time.

Ed

The older models have something called a tipping valve that needs to be removed. It unscrew from one of the openings into the master.

Here's a newer one.

I just did mine, used an airgun as Dan had described. I found that the sealing gromets that cam with my V.B. kit, (2 in the diagram, didn't fit, so I flipped them upside down and it works fine. Just a heads up.

Al's comment about which MC you have is most important.

I'm with the guys, just "showing" a little air to the outlet hole has always worked for me. Catching it with a rag is also a very good suggestion.

When I did the rebuild (PO had installed an earlier MC) the kit from Obsolete Automotive didn't come with the sealing grommets between the reservoir and body so I just re-used the old ones. Shortly thereafter it leaked and I had the pleasure of refinishing the tool shelf on which it sits.

I was so frustrated I just replaced it with a new one from VB for like $100. Period correct and didn't leak, it's still working great but I know others have had different luck with replacement units.

Not to resurface a whole other discussion that has been reviewed many times, but... also an excellent opportunity to get rid of that DOT 3 or 4. (personal preference of course, but my Spit will never again see corrosive brake fluid)

Good luck.

S

Edit: when my new MC arrived from VB it was this one (URO GMC226). Save the middle man and some money.
http://www.amazon.com/URO-Parts-GMC226-Master-Cylinder/dp/B0066QUSW2

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Steve
https://stevew10.wixsite.com/spit16



Edited 1 time(s). Last edit at 2013-10-12 09:47 AM by Manana.

Apply air away from paint finishes. Turning brake fluid into an airborne mist is not good for paint.

In Al's last picture use a pair of needlenose pliers to pull out the little Dowel, which is the #4 in the picture. You might have to put a screwdriver and push the piston back a little, the you can pull out the dowel.

I found that the grommet/seals as shown in the diagram (with the wider part at the top) is probably right. I don't remember which way they were before I pulled the old ones out (shame on me for not being more observant), and although the reservoir did fit into the grommets, it (the reservoir) fit MUCH more snugly with the wider part at the top...it sort of 'snapped' in.
Steve